Maine Forest Ranger Thomas Liba says as far as he can tell, the culprits are taking the sap home and boiling it down to make syrup for personal use. But they're damaging valuable maple trees and dissing landowners who haven't given them permission to be on their property.

Liba says he's seen more sap theft reports in recent years. Illegal taps were even found in a city-owned cemetery in Calais recently.

The best maple trees are high value. They can be used for furniture or cabinet veneers or taken to a sawmill. But when the trees are damaged, they're only suitable for less profitable uses.